Typewriting machine



Oct. 17, 1933. w A, DQBSQN 1,931,064

TYPEWRIIING MACHINE Filed July e.' 1931 lNvENTon:

4 Y This inventionl relates to platen-release mecha# nism oftypewritingmachines.

Patented Oct. 17, 1933 uNlrED'-srA TES *PATENT-OFFICE An object of theinvention is Vto `provide a mechanismeasy to assemble, dismount, cleanor repair', compact, light, durableand cheap, for portable typewriters.V

The usual carrying case is 1placed over the entre typewriter, therebyvlimiting the length of the typewriter-carriage, and, nrecluding` thevuse of thewell-knownplaten-releases, since they `extend considerablybeyond the ends of the carp riage. v

1n the present lnvcntlcnfsubstantlally the .cn-`

tire mechanism is compactly housed within the platen.

writercarri'age does not have tobe lengthened.

A thixnble-cam is made fast to an axiallyslidable platlerl-shaft.l andspreads `a pair of rigid pivoted clutch-levers, which arey mounted inthej platen, said levers normally exerting toward one side of the looseline-space wheel a lateral pres` sure to bind it between twoclampingjaws (connected to the platenlfwith sumcient force for ppositively clutching the platen to said wheel. A very fine adjustment ofthe, clutching force required to couple the platen to the ratchet-wheelis obtained by simply displacing axially. thev fixedV .jaw of the clamp.c l v Y Said adjustment is preferably obtained by pro-l vidingtheprojecting hub of the carrier with a thread, and the fixed jaw Aoftheclamp is made in the form of a disk whichforms a flange upon` a nut,which is threaded upon said hub.. A locknut may be used to ilx saidfixed Jawy in `the desired position. f

The movable jaw of said clamp is a relatively j thin washer, rotatingwith the platen, butwith af certain extent of axial play, and thepressure applied by the clutch-levers may be unifoxnfllydistributedthrough` said washer u ponI a rela-` tively large surface of friction.

-Jarx'ing of the platen duringcase-shifting and` carriage-returnmovements cannot accidentallyV l f release it, the clutchbeing'constantly maintained in closed condition bythe forcing action ofthe clutch-levers and cam'.4 y

The platen of the Underwood portable type-- writer needs to belengthened but little, if any,l and no change is needed in thetypewriter-car r riage. In the clutching and unclutching'opera-- tionsno part ofthe mechanism rubs against the line-space wheel, and theaction of the clutch-V' ing organs is most effectively directed,inasmuch The line-space wheel and its related parts retain their oldpositions, andv the type-` p y release position.

llt in a key-way 26 in the extension 21.

as' there -is exerted a direct lateral`v pressure over a.v large'area ofwheel-surface.` y"

" 'There does not need'to Abe a` single spring or resilient part.

The leftand carri'agel-end-'plate 'ofitheport` fable Underwoodtypewriter is provided with a lengthened internalfhub, insuring aperfect centering and support of the platen and linespace` wheel,l asthe left-hand hub -of -the platen bears upon'the inner end of said hub.The latter also 'affords a long bearing for the shaft.

Other features and `adv tages will .hereinafter appear. f 1 f c I ntheaccompanying drawing,

Figure lisvan axial section of ra platen and its appurtenances, withtheu'clamping device in Figure 2 is similar to Figure 1,;but shows the`clamping deviceclosed; 1

Figure 3 is an'end view with parts taken away for clearness.

Figure 4 isa with parts dissembled. j,

Figure 5 isanother perspective view with parts `A broken away vforclearness. l f f s A platenv 10 is rotatably supported .by means `ofright and V leit *hand platen-shafts x11., and 12, mountedincarriage-end-plates 1-3-. lThe righthand platen-fshaft 11 has a knob 14xed b ysetscrew 15. This'shaftiscomparatively short, and

riage-end plate 13 and into ahub 17 that forms part of theright-handend-wall 18 ofthe platen, rigidly attached by screws19. 'Aset-screw 20 xes shaft 11 toothefhub 17, l Y

The vleft-hand platenshaft 12 isv slidably .mounted within the platen,and is supported at minne; end ln ancxtcn'slcn 21 cr nnb .17. "rncvouter end of theshaft12 vhas a'bearingfin a` centering hollow journal22 on'th'e carriage-end plate 13 and carries `at its'extreme end aknob23 rig- ,y idly attached by a screw,` 24." 4The innerend of theshaft 12 is provided with flattened sides 25 to 'rnc knob 23 is thusconnected welcher rome the extension 21, together with the platen 10, or

to move the shaft 12 endwise to operate a platenrelease mechanism, aswill be'described later. A line-'space wheel 27, loosely mounted attheleft-hand side cf the platen, ls normally clutched to said platen 1K0 bymeansjof a novel mechawhich includes a thimble-cam 28 retained' by`a'pin 29 on the platen-shaft 121at a place ",withinan opening 30 of aplaten-core`31. Ihe cam 28when moved to effective position engagesperspective view of the invention,-

extends -inwardly through a hub 16 on the carthe inner ends 32 oflongarms 33 of a pair'of clutch-operating rigid levers 34. These levers arelodged within a metal shell 35, fitting in the opening and rigidlyattached to the platen-core 31 by screws 36, and are pivoted at 37 inslots 38 provided in the end wall 39 of the platen. Said end wall 39,which thus constitutes a carrier for the clutch-levers 34, is fixed `byscrews 40 within saidshell at the end of the platen, and has a centralhub 41 with a threaded extension 42. To allow the axial displacement ofthe shaft 12, the bore 43 of said hub 41 has a diameter slightly largerthan the cam 28'- The extension 42 bears upon the periphery of thehollow journal 22, so as to insure aperfect parallelism between theplaten and its two shafts, a clearance 44 being provided in that bearingin order to allow a slight tilting of the platen about said journal 22,when, for` repair or inspection, it is desired to remove the platen.Said removal may 'be made by first removing the shaft 11 and the knob23, pushing ther shaft 12 beyond the hollow journal 22, and then itilting the. wholeplaten until itV may. be `disenable Jaw of said'clamp.Said washer is angularly coupled to the end wall 39 by .means ofguide-pins screwed in the outer side of said y through the journal '22,so that its left-hand end 110 wall 39 andtting in corresponding holes 51of the washer 49,v but is free to slideaxially along said pins 50between the end wall 39 and the ratchet-wheel 27. t

The short arms 52y of the levers 34, when the cam 28 spreads the longarms 33 ofthe same, act as a self-releasing wedge, and press upon saidwasher 49, so as to operate the clamping of the ratchet-wheel 27 betweenthe flange 46 and said washer 49. The shape and ratio of leverages ofthe levers 34 are such that a very strong clamping action may beobtained by very smooth and easy pushing-in of the knob 23.I e The shortarms 52, when the levers 34 are released, Just touch said washer 49 andthus allow rthe` platen torotate freely, while the line-space wheel 27is held stationary by means of its usual.

spring-detent roller 53.v The point of contact of each short arm 52 issuiliciently outside of the pivot-center of lever 34 when the line-spacewheel is clamped, tol insure self-releasing movement of said lever whenthe cam 28 is withdrawn.

To connectfthe line-space wheel to 'the platen,

the knob 23, together with the shaft 12 and-cam- 28, 1S pushed endwisetowards the'right until the knob abuts against the end plate 13`(Iiigurej 2) e line-space wheel.

when it 1s desired to disconnect' the 'p'io'ten from the line-spacewheel, the knob 23 is pulled voutto the left until the left-hand end ofthe cam 2s abate the joui-no1 2`2 F1gure 1). 1n this pos-1- tion the cam-28 is fully withdrawnfrom the `ends of the long arms 33 of the levers34, allowing them to rotate about their pivots a7 back to their idle.v

position, and therebyopen the clamp 48,4%, thus` Ltained when the shaft12 is movements.

disconnecting the platen from the ratchet-wheel 27.

It will be noticed that when the levers 34 are rotated in the directionof the arrows (Figure 2), a clamping or clutching force is applieddirectly at two diametrically-opposed middle points on the washer49.'The very strong and well distributed friction may thus be laterallyapplied over a relatively'large surface' of the ratchetwheel 27 by meansof a very short axial displacement of the washer 49.

In assembling the platen-release mechanism of the present invention, thelevers 34 with their pivots 37 and the guide-pins 5() are first mountedon the carrier 39. The flanged nut 46, carrying 'the ratchet-wheel 27and the washer 49, and the lock-nut 48 are then. loosely screwed on thethreadedextension 42. The washer 49 rhas two holes 5l which engage theguide-pins 50.

The compact whole thus formed is inserted in 95 vthe metal shell 35 andsecured thereto by the screws 40. The Vshell is fixed to the platen-core31 by means of the screws 36. The shaft 12, together with itscam 28,` isintroduced ,within the Ahub 4l and said core 31, and the flattened end10U ofthe shaft'12' isv inserted in the key-way- 26. The left-hand endof the platen is now first engaged on the'centering journal22, theclearance y,44 of thel extension42 .facilitating this operation,

and the right-hand end brought'against the hub 105 16. The shaft 11,carrying the knob 14, is introduced through said hub 16' into the hub 17and fixed in position by means of the set-screw 15. The shaft 12 is thuspushed leftward projects Vbeyond the-end plate 13. Knob 23 may now befixed tosaid end by its set-screwv 24. The whole platen-releasemechanism is now mounted in position v'on the typewriter-carriage and isready to'be adjusted so as to correct any 115 excess or insufficiency ofthe clamping force obshifted in the position shown on Figure 2.

vThis adjustmentV is made with Vthe help of a vsuitable Spanner-keyfittingthe notches 47.' By 120 .turning the anged nut 45, 46, differenttrial .positions'there may be determined a position which gives at. thesame time a clampingV or clutching 'action suflicient for positivelycoupling the platen to the ratchet-wheel 27 and a smooth 125 easyshifting in and out of the shafty 12.` When that isjdone, the nut 45 issecured in this 'ad- Justed position with the lock-nut 48.

It will be noticed that* as, in their `operative position, the levers 34press rigidly at the same 133 time on the ratchet-wheel 27, throughwasher 49, and upon the periphery of the cam 2 8, the clamp 46, 49 ispositively prevented from becoming accidentally disconnected by thejarring `of the platen during carriage-returning The .cam 28 is taperedon its right-hand'side in order to give a progressive spreading of thelevers .34 when the shaft 12 is pushed in and is also symmetricallytapered on its left-hand side 143 so as to facilitate the introductionofthe shaft l12 between the ends'of the long arms 33 Vof the levers 34and within the hub v4'1 during the assembling. i

Variations maybe resorted to within the scope ii-t, of the invention,and portions of the improvements may befused without others.

Having thus descrlbedmy'invention, I claim:

1. In a -typewriting machine, in combination, aplaten, a clamp carriedat one end of said platen, lt

and case-shift l a slidable shaft coupled to said platen, a linespacewheel looselyv mounted within said clamp, releasable means controlled by-the axial displacement of said shaft for applying a clamping force uponsaid wheel, means for distributing said clamping force uniformly overarelatively large annular surface of friction on both sides of saidwheel, and means for adjusting said clamping force from the exteriorofsaid platen without any dismounting being required therefor. 2. In v`atypewriting machine, a platen, side.` walls closing both ends of saidplaten, a central projection integral vmh-one offsaidside walls, a angedring constituting the fixed member of a clutch adjustable and lockableon said projection, a washerconstituting the movable member of saidclutch slidably mounted on saidring and coupled to the adjoiningside-wall',fa linespace wheel loosely mounted lon said ring between theflange thereof and said washer, a slid-"' l able shaft angularly coupledto said plate rigid clutch-operating levers pivoted to the' side wallcarrying said projection, and means on said shaftl to control saidclutch through said -levers by axial displacement of said shaft.

' normally applying a lateral pressure on the 'opposite face of saidwheel so as to positively couple the platen to said wheeL-the amount ofsaid pressure depending on the position of said flanged nut onsaid'projection, a slidable shaft coupled to said platen, and meansfixed on said shaft to control said clutch by the axial displacement ofsaid shaft.

4. In a platen-release mechanism for portable typewriters, 'a platen, aline-space ratchet-wheel loosely and independently' mounted at thelefthand end` of said platen,'an abutment adjustably securedto saidplaten on the outer side of said wheel, a pair of diametrically-opposedpivoted rigid levers to apply a clutching pressure on the opposite sideof said wheel, a slidable washer coupled to said platen and interposedbetween said wheel and said levers, so as to distribute uniformly saidclutching pressure over a relatively large annular surface of saidwheel, a slidable shaft coupled to said platen, a manually-operated camcarried on saidv shaft for controlling said levers, and means carried bythe left-hand end plate of the carriage of the typewriter for centeringsaid platen and its related parts with respect to 'said shaft.

5. In a typewriting machine, a platen provided at one end with acylindrical opening, a shell secured to said platen and fitting lwithinsaid opening, a slotted end-wall internally fixed to said shell, a hubwith a lateral threadedextension integral with said end-wall, a nutscrewable on said extension, so 'as to form the fixed wall of a grooveof variable width, an axially-movable washer coupled to said slottedend-wall and l forming the movable wall of said groove, a thin toothedwasher serving as line-space wheel loosely mounted in said groove, acam-shaft angularly coupled to the platen and axially movable withinsaid hub, and releasable rigid instrumentalities actuated by the axialdisplacement of said cam-shaft for normally squeezing said linespacewheel between the xed and movable walls t opening, asiqtted end-wsuinternally `aired to movable washer coupledto saidslotted end-wall "ofsaid groove, so as to positively ceuplebyfriction the platen toisaidwheel. Y 6. Ina typewriting machine, a platen provided `at one end witha cylindrical opening, a shell secured to` said platen and fittingwithin said opening, a slotted end-wall internally fixed to said shell,a hub with a lateral threaded extension integral with said end-wall, anut screwable on said extension and shaped so asto form the fixed wallof Va groove of variable width, an axiallymovable washer coupled tosaidzslottede'nd-wall and forming `the movable wall of said groove, athin toothed washer serving as line-space wheel loosely mounted in saidgroove, a shaft-singularly coupled to the platen and axially movablewithin said hub, a camsecured to said shaft,.and releas- `able rigidclutch-levers pivoted withinvthe slots lof said'end-wall and normallypressing `on said movable wall, so as to squeeze the line-space wheelwithin said groove and thus Apositively-couple by 95 friction the platento said wheel.

7. In a typewriting machine, a platenprovided at one endwith acylindrical opening, a; shell securedtov said platen and fitting withinsaid said shell,v a hub with a lateral threaded extension integral withsaidl end-wall, a nut screwable on said extension andl shaped so as toform theiixed wall of a groove of variable width.- an' axiallyandformingthemovable wall of said groove, a thin toothed washer serving asline-space wheel loosely mounted in'said groove,a shaft angularly.-coupledto the platen and axially movable within said hub, a camsecured-to said shaft, and a pair of Adiametrically-opposed releasablerigid clutch-levers pivoted within the slots of said endwall, each ofsaid levers comprising a long hooked arm 4working in thie. interior ofthe opening of the platen and co-operating with said cam and a short armacting as a wedge on said movable wall, so as to vary the width of saidgroove according. to the position of said cam and normally squeeze theline-space wheel within said groove.

8. In a typewriting machine, a platen provided 1m at one end with acylindrical opening, a shell secured to said platen and fitting withinsaid opening, a slotted end-wall internally 'fixed to said shell, a hubwith a lateralthreaded Vextension integral with said end-wall, a nutscrewable on 125 said extension and shaped so as to form the fixed wallof a groove of variable width, an axiallymovable washer coupledto saidslotted end-wall and forming the movable wall of said groove, a thintoothed washerser'ving as line-space wheel 130 loosely mounted in saidgroove, a shaft angularly coupled tothe platen and axially movablewithin said hub, a cam secured to said shaft, a pair ofdiametrically-opposed releasable rigid clutchlevers having normallytheir long hooked arms 131;l

platen, an independent line-space wheel loosely mounted within saidclamping device, a slidable shaft coupled to said platen and carryingonly an operating knob andy a cam for controlling said clamping device,and a centering hub carried by the left-hand` end-plate of thetypewriter-carriage, said knob co-operating with the outer side uponsaid head within-the platen and bearing. against oneof said jaws toclamp vsaidline-spacey wheel against the otherjaw, a platen-shaft havinga knob onV its outer end and provided with a cam'on its inner end toforce saidv levers to closeL the clampingjaws and hold them'clos'edduringy the normal operation of the machine, said head having acentral opening through which saidshaft extends, said fixed jaw beingscrew-threadved upon said head for fine adjustment of the fixed jaw toregulate the pressure of theclamp,

and means for locking the xed jaw where adjusted;

11. In a typewriting machine, a platen-release mechanism including, incombination, aplaten, a line-'space wheel adjacent one end of saidplaten, a clamping device having a fixed jaw on ythe outer side of saidwheel and a releasable jaw on the innerside, means fastened to saidplaten andforming a mounting for said jaws and'wheel, said" mountingmeans andy fixed jaw being arranged for relative adjustment withoutdismantling the mechanism, said releasable jaw being keyed to saidmounting means to prevent relative rotation while permitting clampingmovement thereof, a 'platen-rotating shaft extending through saidvmounting means, coupled to .said

platen I,for endwise .movement `and having a` cam thereon disposedwithin said platen, and a clamplever device pivoted to said mountingmeans within said platen, for actuation by said cam to a y :pressthereleasable jaw toward 'the fixed jaw,

and thereby couple the line-space wheel, between said jaws, to said.platen or to release said wheel' uponendwise movement of vsaid shaft.k

12. In atypewrlting machine having a carriagey with platen-supporting v`ends, .'the combination with the revoluble platen, of a line-space wheelbetween one platen-endmnd one of said carriageends, a clampingA devicefor releasably coupling rsaid wheel and platen, said device yincluding aAbody-member fastened at said one platen-end and projecting beyond thesame to carry said linespace wheel and clamping device, aplaten-rotating shaft slidably coupled to said platen lat a pointbetween'saiddevice and lthe other platenend,said clampingdevice andshaft ibeing arranged for operation'of said device byfendwise:shaft-movement, said body-memberv having a central openingsubstantially larger than said shaft for admitting the latter, saidshaftextend- Ving outside of said one carriage-end to carry .a platen-knob,said one carriage-end having a hollow journal fitting said opening toform a platen-end bearing about whichthe platen may be ,slightlycocked,and means journaling the other platen-end in the other platen-supportingcarriage-end, said latter journaling means being kretractible to permitwithdrawal of said platen WILLIAM lA. noBsoN. .A

from said carriage.

